The lead Sanford Police investigator who sought manslaughter charges against George Zimmerman told the FBI that a sergeant and two other officers tried to pressure him into making an arrest in the controversial case — even though he didn’t think there was enough evidence.

Sanford Police Officer Chris Serino first made headlines when evidence released in the case showed he sought manslaughter charges against Zimmerman even while his chief publicly said there was no probable cause to arrest him. But a document released late Thursday casts doubt on Serino’s prior sworn affidavit seeking criminal charges, and raises questions about the credibility of the star law-enforcement witness in the murder case against Zimmerman for the shooting death of a black teenager, Miami Gardens high school junior Trayvon Martin..

Telling the FBI that he was concerned that people inside the police department were leaking information, Serino cited Sgt. Arthur Barnes, officers Rebecca Villalona and Trekelle Perkins “as all pressuring him to file charges against Zimmerman after the incident,” an FBI report said. “Serino did not believe he had enough evidence at the time to file charges.”

The summary of Serino’s statement does not mention the race of the officers who allegedly pressured him, but sources told The Miami Herald that Barnes and Perkins are black, and Villalona is married to an African-American man. All three, the source said, had been called in by their supervisor and questioned about leaking information in the case.

A request Thursday evening to the Sanford Police Department for comment about Serino’s statement went unanswered.

“Our position has always been that there’s something going on in the Sanford Police Department,” said Benjamin Crump, an attorney for Trayvon’s family. “All of this is window dressing. What’s important is George Zimmerman’s statements, which are inconsistent and factually impossible.”

Serino, a 15-year veteran of the department who was a major-crimes investigator, was demoted last month to overnight patrol. Tapes of his interviews with Zimmerman show him poking holes in the former neighborhood watch volunteer’s account of what happened the night he killed Trayvon. Serino told the FBI that Zimmerman had a “little hero complex” and sounded “scripted.” However, he said he believed Zimmerman targeted Trayvon because of his attire, the circumstances and recent burglaries in the area, not the color of the teen’s skin.

In his FBI interview, Serino accused Sgt. Barnes of being “friendly” with Tracy Martin, Trayvon’s father. He said Tracy Martin at first understood why no charges were filed, but later changed coursse and accused Zimmerman of racial profiling.

Crump denied that Tracy Martin ever changed postures. Martin, he said, sought legal counsel the very day Serino told him no charges would be filed.

Records released Thursday show that Sgt. Barnes, a 25-year veteran of the department, told the FBI that he believed the black community would be “in an uproar” if Zimmerman was not charged. “The community will be satisfied if an arrest takes place,” the FBI quoted him saying. Barnes “felt the shooting was not racially motivated, but it was a man shooting an unarmed kid.”